U.S. patent application number 17/076239 was filed with the patent office on 2021-02-04 for antenna module.
The applicant listed for this patent is Murata Manufacturing Co., Ltd.. Invention is credited to Hirotsugu MORI, Takaki MURATA, Kengo ONAKA, Kaoru SUDO, Hideki UEDA.
Application Number | 20210036428 17/076239 |
Document ID | / |
Family ID | 1000005223421 |
Filed Date | 2021-02-04 |
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United States Patent
Application |
20210036428 |
Kind Code |
A1 |
UEDA; Hideki ; et
al. |
February 4, 2021 |
ANTENNA MODULE
Abstract
A plurality of multi-band antenna elements operable at a
plurality of frequencies constitutes an array antenna. An antenna
drive unit selects at least some of the multi-band antenna elements
from the plurality of multi-band antenna elements in accordance
with one operation frequency selected from the plurality of
operation frequencies, and causes the selected multi-band antenna
elements to operate.
Inventors: |
UEDA; Hideki; (Kyoto,
JP) ; SUDO; Kaoru; (Kyoto, JP) ; ONAKA;
Kengo; (Kyoto, JP) ; MORI; Hirotsugu; (Kyoto,
JP) ; MURATA; Takaki; (Kyoto, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Murata Manufacturing Co., Ltd. |
Kyoto |
|
JP |
|
|
Family ID: |
1000005223421 |
Appl. No.: |
17/076239 |
Filed: |
October 21, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2019/016476 |
Apr 17, 2019 |
|
|
|
17076239 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01Q 21/065 20130101;
H01Q 5/378 20150115; H01Q 21/28 20130101; H01Q 13/08 20130101; H01Q
5/307 20150115 |
International
Class: |
H01Q 13/08 20060101
H01Q013/08; H01Q 21/06 20060101 H01Q021/06; H01Q 21/28 20060101
H01Q021/28; H01Q 5/307 20060101 H01Q005/307; H01Q 5/378 20060101
H01Q005/378 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2018 |
JP |
2018-085146 |
Sep 3, 2018 |
JP |
2018-164421 |
Claims
1. An antenna module comprising: an array antenna comprising a
plurality of multi-band unit antennas, the array antenna being
configured to operate at a plurality of operation frequencies; and
an antenna driver configured to select at least two multi-band unit
antennas in accordance with a selected operation frequency, and to
operate the selected multi-band unit antennas, wherein the antenna
driver comprises a plurality of feed lines, wherein each of the
plurality of multi-band unit antennas comprises a plurality of
conductor patterns, and each of the plurality of conductor patterns
are configured to radiate radio frequency signals at the plurality
of operation frequencies, and wherein the conductor patterns of the
selected multi-band unit antennas are configured to radiate a radio
frequency signal at the selected operation frequency, and are
coupled to one of the plurality of feed lines.
2. The antenna module according to claim 1, wherein a maximum value
of a pitch of the plurality of multi-band unit antennas is less
than a free space wavelength corresponding to a highest one of the
plurality of operation frequencies.
3. The antenna module according to claim 1, wherein the antenna
driver comprises: a controller configured to output a selection
signal configured to select a combination of the at least two
multi-band unit antennas in accordance the selected operation
frequency, and a radio frequency integrated circuit configured to
feed power to the selected multi-band unit antennas, and to not
feed power to non-selected multi-band unit antennas, based on the
selection signal.
4. The antenna module according to claim 3, wherein the radio
frequency integrated circuit is configured to input a radio
frequency signal to the selected multi-band unit antennas, and to
not input the radio frequency signal to the non-selected multi-band
unit antennas.
5. The antenna module according to claim 1, wherein the conductor
patterns of the non-selected multi-band unit antennas are not
coupled to any of the plurality of feed lines.
6. The antenna module according to claim 1, wherein the plurality
of multi-band unit antennas are arranged in a two-dimensional
matrix.
7. The antenna module according to claim 1, wherein the plurality
of multi-band unit antennas are arranged at positions corresponding
to a triangular grid.
8. The antenna module according to claim 1, wherein the antenna
driver is configured to select the at least two multi-band unit
antennas such that a maximum value of a pitch of the selected
multi-band unit antennas is equal to or less than a free space
wavelength corresponding to the selected operation frequency.
9. The antenna module according to claim 1, further comprising: a
dielectric substrate in or on which the plurality of multi-band
unit antennas are located; and a first ground conductor layer in
the dielectric substrate, wherein: each of the plurality of
multi-band unit antennas comprises: a first conductor pattern above
the first ground conductor layer in a thickness direction of the
dielectric substrate, and a second conductor pattern above the
first conductor pattern so as to overlap the first conductor
pattern when the antenna module is seen in a plan view, and the
antenna driver comprises: a first feed line network configured to
selectively excite the first conductor patterns of the selected
multi-band unit antennas, and to not excite the first conductor
patterns of the non-selected multi-band unit antennas, and a second
feed line network configured to excite the second conductor
patterns of all of the plurality of multi-band unit antennas.
10. The antenna module according to claim 9, wherein each of the
plurality of multi-band unit antennas further comprises a via
conductor that connects the first conductor pattern to the first
ground conductor layer.
11. The antenna module according to claim 10, wherein: the first
feed line network comprises a first feed line coupled to the first
conductor pattern of the selected multi-band unit antennas, and the
second feed line network comprises a second feed line that extends
from a lower side to an upper side of the first conductor pattern,
and that is coupled to the second conductor pattern.
12. The antenna module according to claim 11, wherein in each of
the plurality of multi-band unit antennas, the via conductor is
between a first coupling point and a second coupling point, the
first coupling point being where the first conductor pattern and
the first feed line are coupled, and the second coupling point
being where the second conductor pattern and the second feed line
are coupled.
13. The antenna module according to claim 12, wherein the via
conductors surround the second coupling point when the antenna
module is seen in the plan view.
14. The antenna module according to claim 9, further comprising a
second ground conductor layer that is in a same layer as the first
conductor pattern, and that is connected to the first ground
conductor layer.
15. The antenna module according to claim 9, wherein: the first
feed line network comprises a first radio frequency integrated
circuit that is mounted on the dielectric substrate and that is
configured to transmit and receive radio frequency signals,
respectively, to and from the first conductor pattern, and the
second feed line network comprises a second radio frequency
integrated circuit that is mounted on the dielectric substrate, and
that is configured to transmit and receive radio frequency signals,
respectively, to and from the second conductor pattern.
16. The antenna module according to claim 9, wherein: the first
feed line network and the second feed line network comprise,
respectively, a first radio frequency circuit configured to excite
the first conductor pattern and a second radio frequency circuit
configured to excite the second conductor pattern, and the first
radio frequency circuit and the second radio frequency circuit are
in a single integrated circuit.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of International Application No.
PCT/JP2019/016476 filed on Apr. 17, 2019 which claims priority from
Japanese Patent Application No. 2018-085146 filed on Apr. 26, 2018,
and claims priority from Japanese Patent Application No.
2018-164421 filed on Sep. 3, 2018. The contents of these
applications are incorporated herein by reference in their
entireties.
BACKGROUND OF THE DISCLOSURE
Field of the Disclosure
[0002] The present disclosure relates to an antenna module.
Description of the Related Art
[0003] An array antenna system capable of quickly forming a beam
pattern conforming to a communication direction of a radio signal
is disclosed in Patent Document 1 below. The array antenna system
includes a plurality of antenna elements arranged at predetermined
intervals in a row direction and a column direction, and control
means configured to selectively operate at least two antenna
elements among the plurality of antenna elements along the
direction of a radio signal to be received.
[0004] Patent Document 2 below discloses a microstrip antenna in
which a plurality of antenna elements (patches) is laminated, and a
coaxial power feeding portion is provided to each antenna element.
The microstrip antenna is capable of supporting two or multiple
frequencies by antenna elements in a plurality of layers.
[0005] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2008-167401
[0006] Patent Document 2: Japanese Unexamined Patent Application
Publication No. 2010-226633
BRIEF SUMMARY OF THE DISCLOSURE
[0007] The array antenna system disclosed in Patent Document 1 is
capable of forming a suitable beam pattern in accordance with a
communication direction of a radio signal at a specific frequency,
but is not capable of supporting a plurality of radio signals
(radio waves) of different frequencies.
[0008] When the array antenna is constituted of the microstrip
antenna disclosed in Patent Document 2, it is possible to support
two frequencies or multiple frequencies by antenna elements in a
plurality of layers. However, when the interval between radiating
elements is made suitable in one frequency band, the interval
between the radiating elements may be deviated from a suitable
range in other frequency bands.
[0009] An object of the present disclosure is to provide an antenna
module capable of supporting a plurality of frequencies and capable
of making the interval between the radiating elements suitable at
each frequency.
[0010] According to one aspect of the present disclosure, there is
provided an antenna module including:
[0011] a plurality of multi-band antenna elements configured to
constitute an array antenna and operable at a plurality of
operation frequencies; and
[0012] an antenna drive unit configured to select at least two
multi-band antenna elements among the plurality of multi-band
antenna elements in accordance with one operation frequency
selected from the plurality of operation frequencies, and to cause
the multi-band antenna elements that are selected among the
plurality of multi-band antenna elements to operate.
[0013] By selecting the combination of the multi-band antenna
elements to be operated in accordance with the operation frequency,
it is possible to set the interval between the multi-band antenna
elements to be operated to a preferred value.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] FIG. 1A is a schematic view of an antenna module according
to a first embodiment, and FIG. 1B is a sectional view illustrating
an example of one multi-band antenna element.
[0015] FIG. 2 is a block diagram of the antenna module according to
the first embodiment.
[0016] FIG. 3A and FIG. 3B are diagrams illustrating multi-band
antenna elements in an operation state when 39 GHz and 28 GHz are
selected as operation frequencies, respectively.
[0017] FIG. 4 is a block diagram of the antenna module in the
operation state illustrated in FIG. 3A when the antenna module is
in a transmission state.
[0018] FIG. 5 is a block diagram of the antenna module in the
operation state illustrated in FIG. 3B when the antenna module is
in the transmission state.
[0019] FIG. 6A and FIG. 6B are plan views when the antenna module
according to the first embodiment which is the simulation target is
operated at 39 GHz and 28 GHz, respectively.
[0020] FIG. 7A and FIG. 7B are plan views of patch array antennas
for 39 GHz and 28 GHz according to a comparative example,
respectively.
[0021] FIG. 8A and FIG. 8B are graphs illustrating simulation
results of directivity characteristic of the antenna module
according to the first embodiment and the comparative example at 39
GHz and 28 GHz, respectively.
[0022] FIG. 9A, FIG. 9B, and FIG. 9C are plan views of one
multi-band antenna element used in an antenna module according to a
second embodiment and a modification thereof.
[0023] FIG. 10A is a plan view of a plurality of multi-band antenna
elements of an antenna module according to a third embodiment, and
FIG. 10B, FIG. 10C, FIG. 10D, and FIG. 10E are diagrams
illustrating an example of a combination of multi-band antenna
elements to be operated, respectively.
[0024] FIG. 11A is a plan view of the plurality of multi-band
antenna elements of the antenna module according to the third
embodiment, and FIG. 11B is a diagram illustrating an example of a
combination of the multi-band antenna elements to be operated.
[0025] FIG. 12 is a perspective view of a conductor portion and a
diagram illustrating a path of a feed line system of an antenna
module according to a fifth embodiment.
[0026] FIG. 13A is a plan view of an antenna module according to a
sixth embodiment and a schematic view illustrating a connection
aspect of a feed line, and FIG. 13B is a sectional view taken along
the dash-dotted line 13B-13B in FIG. 13A.
[0027] FIG. 14A is a plan view of regions of two first conductor
patterns of an antenna module according to a seventh embodiment,
and FIG. 14B is a sectional view taken along the dash-dotted line
14B-14B in FIG. 14A.
[0028] FIG. 15A is a sectional view of an antenna module according
to an eighth embodiment, and FIG. 15B and FIG. 15C are sectional
views illustrating antenna modules according to modifications of
the eighth embodiment.
[0029] FIG. 16A and FIG. 16B are sectional views of antenna modules
according to a ninth embodiment and a first modification thereof,
respectively.
[0030] FIG. 17 is a sectional view of an antenna module according
to a second modification of the ninth embodiment.
[0031] FIG. 18 is a sectional view of an antenna module according
to a reference example.
DETAILED DESCRIPTION OF THE DISCLOSURE
First Embodiment
[0032] An antenna module according to a first embodiment will be
described with reference to the drawings in FIG. 1A to FIG. 6B.
[0033] FIG. 1A is a schematic diagram of the antenna module
according to the first embodiment. The antenna module according to
the first embodiment includes a plurality of multi-band antenna
elements 20 (unit antennas) and an antenna drive unit 50. Each of
the plurality of multi-band antenna elements 20 is operable at a
plurality of frequencies. The plurality of multiband antenna
elements 20 is arranged in a two-dimensional matrix with four rows
and four columns, for example, and constitutes an array antenna 21.
It should be noted that the number of rows and the number of
columns are not limited to four. A pitch Px in the row direction
and a pitch Py in the column direction between the multi-band
antenna elements 20 are equal to each other. The pitch in a
45.degree. oblique direction becomes ((2.sup.1/2)/2)Px. Here, the
"pitch in oblique direction" does not refer to the pitch of two
multi-band antenna elements 20 adjacent to each other in oblique
direction, but refers to the pitch of lines when focusing on a
plurality of lines constituted of the multi-band antenna elements
20 arranged in oblique direction. The pitch Px in the row direction
and the pitch Py in the column direction are the largest among the
pitches in various directions. It is preferable that the pitch Px
and the pitch Py be smaller than the free space wavelength
determined by the highest operation frequency among the plurality
of operation frequencies. For example, when the highest operation
frequency is 39 GHz, the free space wavelength determined by the
frequency is about 7.7 mm. Therefore, it is preferable that the
pitch Px and the pitch Py be set to be equal to or less than 7.7
mm.
[0034] The antenna drive unit 50 includes a plurality of feed lines
51, a radio frequency integrated circuit element 52, a baseband
integrated circuit element 53, and a controller 54. The baseband
integrated circuit element 53 performs baseband signal processing.
The radio frequency integrated circuit element 52 performs signal
processing for radio frequency band. The controller 54 selects one
operation frequency for the array antenna 21 to be operated from a
plurality of operation frequencies. Furthermore, a combination of
multi-band antenna elements 20 to be operated is determined from
the plurality of multi-band antenna elements 20 in accordance with
the selected operation frequency. Upon determining the combination
of the multi-band antenna elements 20 to be operated, the
controller 54 outputs a selection signal for specifying the
combination of the multi-band antenna elements 20 to be operated to
the radio frequency integrated circuit element 52. The controller
54 stores the combination of the multi-band antenna elements 20 to
be operated corresponding to each of the plurality of operation
frequencies. The radio frequency integrated circuit element 52 has
a function of feeding power to the selected multi-band antenna
elements 20, and not feeding power to the remaining multi-band
antenna elements 20.
[0035] FIG. 1B is a sectional view illustrating an example of one
multi-band antenna element 20. The multi-band antenna element 20 is
provided in or on a dielectric substrate 30. In the present
description, the thickness direction of the dielectric substrate 30
corresponds to the up-down direction. A first ground conductor
layer 31 is provided in the dielectric substrate 30. The multi-band
antenna element 20 is disposed at a position different from that of
the first ground conductor layer 31 in the thickness direction of
the dielectric substrate 30. A direction from the first ground
conductor layer 31 toward the multi-band antenna element 20 is
defined as an "upward direction", and an opposite direction thereof
is defined as a "downward direction". Each of the multi-band
antenna elements 20 includes a plurality of conductor patterns, for
example, a first conductor pattern 201 and a second conductor
pattern 202. In plan view, the first conductor pattern 201 and the
second conductor pattern 202 overlap with each other. For example,
the second conductor pattern 202 is disposed inside the first
conductor pattern 201.
[0036] The feed line 51 is coupled to the second conductor pattern
202. Specifically, the second conductor pattern 202 is
electromagnetically coupled to the feed line 51. For example, the
feed line 51 extends downward from a lower surface of the second
conductor pattern 202 (surface facing downward direction), passes
through a clearance hole provided in the first conductor pattern
201 and a clearance hole provided in the first ground conductor
layer 31, and reaches a region below the first ground conductor
layer 31. In the present description, the term "coupled" includes a
coupling that is electrically directly connected, and an
electromagnetic coupling.
[0037] The size of the first conductor pattern 201 and the size of
the second conductor pattern 202 are different from each other, and
resonate at mutually different frequencies. When the signal of the
resonant frequency of the second conductor pattern 202 is supplied
to the second conductor pattern 202 via the feed line 51 directly
connected thereto, the multi-band antenna element 20 operates at
the resonant frequency of the second conductor pattern 202. When
the signal at the resonant frequency of the first conductor pattern
201 is supplied to the first conductor pattern 201 via the feed
line 51 electromagnetically coupled thereto, the multi-band antenna
element 20 operates at the resonant frequency of the first
conductor pattern 201. Accordingly, the multi-band antenna element
20 operates at two different frequencies that are the resonant
frequency of the first conductor pattern 201 and the resonant
frequency of the second conductor pattern 202.
[0038] FIG. 2 is a block diagram of the antenna module according to
the first embodiment. Hereinafter, the function of the antenna
drive unit 50 will be described.
[0039] An intermediate frequency signal is inputted from the
baseband integrated circuit element 53 to an up-down conversion
mixer 61 via an intermediate frequency amplifier 60. A radio
frequency signal up-converted by the up-down conversion mixer 61 is
inputted to a power divider 63 via a transmission/reception
changeover switch 62. Each of the radio frequency signals obtained
by division by the power divider 63 is inputted to the multi-band
antenna element 20 via a phase shifter 64, an attenuator 65, a
transmission/reception changeover switch 66, a power amplifier 67,
a transmission/reception changeover switch 69, and the feed line
51.
[0040] The radio frequency signal received by each of the
multi-band antenna elements 20 is inputted to the power divider 63
via the feed line 51, the transmission/reception changeover switch
69, a low-noise amplifier 68, the transmission/reception changeover
switch 66, the attenuator 65, and the phase shifter 64. The radio
frequency signal combined by the power divider 63 is inputted to
the up-down conversion mixer 61 via the transmission/reception
changeover switch 62. The intermediate frequency signal
down-converted by the up-down conversion mixer 61 is inputted to
the baseband integrated circuit element 53 via the intermediate
frequency amplifier 60.
[0041] The radio frequency integrated circuit element 52 includes
transmission/reception changeover switches 62, 66, and 69, the
power amplifier 67, the low-noise amplifier 68, the attenuator 65,
the phase shifter 64, the power divider 63, the up-down conversion
mixer 61, and the intermediate frequency amplifier 60. Note that it
is acceptable that the transmission/reception changeover switches
62, 66, and 69, the power amplifier 67, the low-noise amplifier 68,
the attenuator 65, the phase shifter 64, and the power divider 63
are configured in an integrated manner, and the up-down conversion
mixer 61 and the intermediate frequency amplifier 60 are in a
separate chip.
[0042] The controller 54 outputs a selection signal for specifying
the combination of the multi-band antenna elements 20 to be
operated to the baseband integrated circuit element 53. The
selection signal is outputted to the radio frequency integrated
circuit element 52 via the baseband integrated circuit element 53,
and the states of the transmission/reception changeover switches 66
and 69 are switched by the selection signal. Each of the
transmission/reception changeover switches 66 and 69 is set to one
of three states that are a transmission state, a reception state,
and a neutral state. The multi-band antenna elements 20
corresponding to the transmission/reception changeover switches 66
and 69 set to the transmission state or the reception state are in
an operation state. The multi-band antenna elements 20
corresponding to the transmission/reception changeover switches 66
and 69 set to the neutral state are in a non-operation state. No
power is fed to the multi-band antenna elements 20 in the
non-operation state. The transmission/reception changeover switches
66 and 69 are for the time division duplexing communication (TDD)
scheme.
[0043] Next, a combination of the multi-band antenna elements 20 to
be in the operation state will be described with reference to FIG.
3A and FIG. 3B.
[0044] FIG. 3A and FIG. 3B are diagrams illustrating multi-band
antenna elements 20 in the operation state when 39 GHz and 28 GHz
are selected as operation frequencies, respectively. In FIG. 3A and
FIG. 3B, the multi-band antenna elements 20 in the operation state
are hatched.
[0045] When 39 GHz is selected as the operation frequency, all of
the multi-band antenna elements 20 are operated as illustrated in
FIG. 3A. At this time, the pitch Px in the row direction and the
pitch Py in the column direction each correspond to the maximum
value of the pitch of the multi-band antenna elements 20 in the
operation state, and the value thereof is 3.8 mm. When 28 GHz is
selected as the operation frequency, as illustrated in FIG. 3B, the
multi-band antenna elements 20 in the operation state are
distributed in a checkered pattern. At this time, the pitch Ps in
the oblique direction corresponds to the maximum value of the pitch
of the multi-band antenna elements 20 in the operation state, and
the value thereof is 5.4 mm. In either case, the maximum value of
the pitch of the multi-band antenna elements 20 in the operation
state is about 1/2 of the free space wavelength determined by the
operation frequency. With this configuration, the angle in which
beamforming is possible expands, and side lobes are suppressed.
[0046] FIG. 4 is a block diagram of the antenna module in the
operation state illustrated in FIG. 3A when the antenna module is
in the transmission state. All of the transmission/reception
changeover switches 66 and 69 are set to the transmission state.
Therefore, all of the multi-band antenna elements 20 are brought
into the operation state. In order to switch the antenna module to
be in the reception state, all of the transmission/reception
changeover switches 66 and 69 are switched to the reception
state.
[0047] FIG. 5 is a block diagram of the antenna module in the
operation state illustrated in FIG. 3B when the antenna module is
in the transmission state. The transmission/reception changeover
switches 66 and 69 corresponding to the multi-band antenna elements
20 to be operated are set to the transmission state, and the
transmission/reception changeover switches 66 and 69 corresponding
to the multi-band antenna elements 20 not to be operated are set to
the neutral state. With this configuration, no power is fed to the
multi-band antenna elements 20 not to be operated. In order to
switch the antenna module to be in the reception state, only the
transmission/reception changeover switches 66 and 69 set to the
transmission state need to be switched to the reception state. The
multi-band antenna element 20 set to the neutral state may remain
in the neutral state.
[0048] Next, an excellent effect of the first embodiment will be
described with reference to the drawings in FIG. 6A to FIG. 8B. The
directivity characteristic of the antenna module according to the
first embodiment and an antenna module according to a comparative
example were obtained by a simulation. The simulation will be
described below.
[0049] FIG. 6A and FIG. 6B are plan views of the simulation target
antenna module according to the first embodiment. The multi-band
antenna elements 20 are arranged in a matrix with four rows and
four columns. The pitch Px in the row direction and the pitch Py in
the column direction are both 3.8 mm. Each of the multi-band
antenna elements 20 includes a radiation conductor pattern (patch)
for 39 GHz, and a radiation conductor pattern (patch) for 28 GHz
larger than that for 39 GHz.
[0050] When the multi-band antenna elements 20 are operated at 39
GHz, the power is fed to all of the radiation patterns for 39 GHz.
In FIG. 6A, the radiation patterns that are power feed targets are
hatched. When operated at 28 GHz, the radiation patterns that are
power feed targets are selected such that the radiation patterns
for 28 GHz that are power feed targets are arranged in a checkered
pattern. In FIG. 6B, the radiation patterns that are power feed
targets are hatched. The shortest pitch Ps in oblique direction is
about 5.37 mm.
[0051] FIG. 7A is a plan view of a patch array antenna for 39 GHz
according to the comparative example. The patch antennas are
arranged in a matrix with four rows and four columns. The pitch Px
in the row direction and the pitch Py in the column direction are
both 3.8 mm.
[0052] FIG. 7B is a plan view of a patch array antenna for 28 GHz
according to the comparative example. The patch array antenna
according to the comparative example is constituted of eight patch
antennas. The patch array antenna is formed by removing one at a
corner from nine patch antennas arranged in a matrix with three
rows and three columns. The one patch at a corner is removed
because the number of radiation patterns is to be matched to the
number of the radiation patterns that are power feed targets in the
antenna module according to the first embodiment (FIG. 6B). The
pitch Px in the row direction and the pitch Py in the column
direction are both 5.4 mm.
[0053] FIG. 8A and FIG. 8B are graphs describing the simulation
results of directivity characteristic of the antenna modules
according to the first embodiment and the comparative example. FIG.
8A describes the directivity characteristic when the operation
frequency is 39 GHz (FIG. 6A and FIG. 7A), and FIG. 8B describes
the directivity characteristic when the operation frequency is 28
GHz (FIG. 6B and FIG. 7B). In the horizontal axis of the graphs
described in FIG. 8A and FIG. 8B, the tilt angle from the normal
direction of a plane in which the multi-band antenna elements 20
are arranged to a row direction is expressed in the unit of
".degree.", and in the vertical axis, an antenna gain is expressed
in the unit of "dB (DirTotal)". In FIG. 8A and FIG. 8B, the solid
line of the graph indicates the simulation result of the antenna
gain of the antenna module according to the first embodiment. In
FIG. 8A and FIG. 8B, the broken line of the graph indicates the
simulation result of the antenna gain of the antenna module
according to the comparative example.
[0054] As illustrated in FIG. 8A, it is found that when all of the
multi-band antenna elements 20 of the antenna module according to
the first embodiment are operated (FIG. 6A), the directivity
characteristic substantially equivalent to that of the existing
patch array antenna for 39 GHz (FIG. 7A) is obtained. As
illustrated in FIG. 8B, it is found that when only some of the
multi-band antenna elements of the antenna module according to the
first embodiment is operated (FIG. 6B), the directivity
characteristic substantially equivalent to that of the existing
patch array antenna for 28 GHz (FIG. 7B) is obtained. That is, in
the antenna module according to the first embodiment, without
preparing two antenna arrays, it is possible to ensure the same
performance as that of the configuration in which two antenna
arrays are disposed. With this configuration, it is possible to
reduce the size of the antenna module.
[0055] In the past, in the case of transmitting and receiving radio
waves in two different frequencies, two patch array antennas having
different pitches have to be prepared. In contrast, in the first
embodiment, it is possible to transmit and receive radio waves in
two different frequencies by making different combinations
(grouping) of the multi-band antenna elements 20 to be operated in
the one array antenna 21 (FIG. 1A). By making the combination of
the multiple multi-band antenna elements 20 different, it is
possible to make the pitch of the multi-band antenna elements 20
suitable in accordance with the operation frequency. For example,
it is possible to set the pitch of the multi-band antenna elements
20 to about 1/2 of the free space wavelength determined by the
operation frequency. As the result, it is possible to make the
directivity characteristic, when the antenna module according to
the first embodiment is operated at each frequency, substantially
equal to the directivity characteristic of the existing patch array
antenna.
[0056] It is preferable that the maximum value among the pitches
between the multi-band antenna elements 20 in various directions be
made smaller than the free space wavelength determined by the
highest operation frequency among the plurality of operation
frequencies. By configuring as described above, it is possible to
suppress grating lobes, and it is possible to obtain an excellent
effect that the aperture efficiency as an array antenna is
increased. It is more preferable that the maximum value of the
pitch of the multi-band antenna elements 20 be set to 1/2 or less
of the free space wavelength determined by the highest operation
frequency among the plurality of operation frequencies. By
configuring as described above, it is possible to obtain an
excellent effect that the beamforming may be effectively performed.
That is, it is possible to obtain an excellent effect that the
angle in which the beamforming is possible expands, and the side
lobes are suppressed.
[0057] In the first embodiment, the plurality of multi-band antenna
elements 20 is arranged in a matrix. By performing the selection
from the plurality of multi-band antenna elements 20 arranged in a
matrix and the phase control of each multi-band antenna element 20,
it is possible to obtain an effect that the degree of freedom in
beamforming is increased.
[0058] When a frequency other than the highest operation frequency
among the plurality of operation frequencies is selected, it is
preferable to select the multi-band antenna element 20 such that
the maximum value of the pitch of the plurality of the multi-band
antenna elements 20 to be selected becomes equal to or less than
the free space wavelength determined by the selected operation
frequency. When the multi-band antenna elements 20 to be operated
are selected as described above, it is possible to suppress the
grating lobes at the selected operation frequency, and it is
possible to obtain an excellent effect that the aperture efficiency
of the array antenna is increased. When the multi-band antenna
elements 20 other than the selected multi-band antenna elements 20
are put in the non-operation state, the number of ports used by the
radio frequency integrated circuit element 52 is decreased, and
thus it is possible to reduce power consumption. Even when the
power consumption is reduced, a decrease in the gain as an array
antenna is small.
[0059] Next, a modification of the first embodiment will be
described.
[0060] In the first embodiment, the plurality of multi-band antenna
elements 20 is arranged in a two-dimensional matrix along a planer
plane parallel to the surface of the dielectric substrate 30 (FIG.
1B), but the present disclosure is not limited to the planer plane,
and the plurality of multi-band antenna elements 20 may be arranged
along a spherical plane or an arbitrarily curved plane. For
example, the plurality of multi-band antenna elements 20 may be
disposed along a skin of a fuselage of an aircraft. Further, the
plurality of multi-band antenna elements 20 may be arranged in a
one-dimensional shape along a straight line or a curved line. When
the plurality of multi-band antenna elements 20 is arranged along a
planer plane, since the radiation directions of all of the
multi-band antenna elements 20 are the same, an effect is obtained
that the gain is increased. When the plurality of multi-band
antenna elements 20 is arranged along a curved plane, since the
radiation directions of the plurality of multi-band antenna
elements 20 are oriented in various directions, an effect is
obtained that the overall directivity is broadened. In the first
embodiment, the plurality of multi-band antenna elements 20 is
arranged at equal pitches, but it is not always necessary to
arrange the plurality of multi-band antenna elements 20 at equal
pitches. The array antenna 21 may be constituted by the plurality
of multi-band antenna elements 20 arranged at unequal pitches.
[0061] In the first embodiment, by setting the
transmission/reception changeover switches 66 and 69 (FIG. 2) to
the neutral state, the corresponding multi-band antenna elements 20
are brought into the non-operation state. In addition, by making
the power amplifier 67 and the low-noise amplifier 68 not to
operate, the corresponding multi-band antenna elements 20 may be
brought into the non-operation state. Further, an on/off switch may
be inserted between the transmission/reception changeover switch 66
and the power amplifier 67, and between the low-noise amplifier 68
and the transmission/reception changeover switch 66. By turning on
the on/off switch, the corresponding multi-band antenna elements 20
may be brought into the operation state, and by turning off the
on/off switch, the corresponding multi-band antenna elements 20 may
be brought into the non-operation state.
Second Embodiment
[0062] Next, an antenna module according to a second embodiment
will be described with reference to FIG. 9A, FIG. 9B, and FIG. 9C.
Hereinafter, the description of the configuration common to that of
the antenna module according to the first embodiment will be
omitted.
[0063] FIG. 9A is a plan view of one multi-band antenna element 20
used in an antenna module according to a second embodiment. In the
first embodiment, each of the multi-band antenna elements 20 is
constituted of the first conductor pattern 201 and the second
conductor pattern 202 laminated in the thickness direction (FIG.
1B). The multi-band antenna element 20 according to the second
embodiment is constituted of a plurality of conductor patterns 203,
204, and 205 having different dimensions disposed in the same
plane.
[0064] In each of the multi-band antenna elements 20 according to
the second embodiment, the smallest pair of the conductor patterns
203 is disposed in the innermost side, for example. A pair of the
conductor patterns 204 that are larger than the pair of the
conductor patterns 203 are disposed outside the pair of the
conductor patterns 203. Further, the largest pair of the conductor
patterns 205 are disposed outside the conductor patterns 204. The
conductor patterns 203, 204, and 205 have a shape elongated in one
direction respectively, and are disposed in parallel to one
another. These conductor patterns 203, 204, 205 are coupled to a
feed line 210 via a slot 209. The slot 209 is provided in a ground
conductor disposed between the conductor patterns 203, 204, and 205
and the feed line 210 in the thickness direction. In the plan view,
the slot 209 has a shape elongated in a direction substantially
orthogonal to the longitudinal direction of each of the conductor
patterns 203, 204, and 205, and intersects with each of the
conductor patterns 203, 204, and 205. The multi-band antenna
element 20 operates at three different frequencies corresponding to
the dimensions of the conductor patterns 203, 204, and 205.
[0065] FIG. 9B is a plan view of one multi-band antenna element 20
of an antenna module according to a modification of the second
embodiment. The multi-band antenna element 20 according to the
present modification includes a conductor pattern 206 having a
cross shape and a sub-array constituted of four conductor patterns
207. The conductor pattern 206 operates at a relatively low
frequency, and the sub-array operates at a relatively high
frequency.
[0066] FIG. 9C is a plan view of one multi-band antenna element 20
of an antenna module according to another modification of the
second embodiment. Each of the multi-band antenna elements 20
according to the present modification is constituted of a
rectangular conductor pattern 208 having two slots 211 provided
therein. The two slots 211 are arranged slightly inside the short
sides of the rectangular conductor pattern 208, in parallel to the
short sides. In the multi-band antenna element 20 according to the
present modification, a first resonant mode and a third resonant
mode are used.
[0067] In the first resonant mode, the amplitude of the current
flowing in the longitudinal direction of the conductor pattern 208
becomes zero at both ends, and the point where the amplitude
becomes the maximum appears in one place at the center in the
longitudinal direction. In the third resonant mode, the points
where the amplitude of the current flowing in the longitudinal
direction of the conductor pattern 208 becomes the maximum appear
in three places in the longitudinal direction, and the amplitude
becomes zero between points at which the amplitude is maximum and
at both ends. In the present modification, the region at both ends
among the regions in which the current amplitude in the third
resonant mode becomes the maximum is reduced by the slot 211,
whereby the current distribution close to the current distribution
in the first resonant mode is obtained in the third resonant mode.
With this configuration, a multi-band operation is performed.
[0068] It is possible to obtain an excellent effect similar to that
of the first embodiment even when the multi-band antenna element 20
according to the second embodiment or the modification thereof is
used instead of the multi-band antenna element 20 of the antenna
module according to the first embodiment (FIG. 1B). Further, other
multi-band antenna elements may be used.
Third Embodiment
[0069] Next, an antenna module according to a third embodiment will
be described with reference to FIG. 10A to FIG. 10E. Hereinafter,
the description of the configuration common to that of the antenna
module according to the first embodiment will be omitted.
[0070] FIG. 10A is a plan view of the plurality of multi-band
antenna elements 20 of an antenna module according to a third
embodiment. In the first embodiment, 16 multi-band antenna elements
20 (FIG. 1A) are arranged in a matrix with four rows and four
columns. In the third embodiment, 36 multi-band antenna elements 20
are arranged in a matrix with six rows and six columns. The pitches
in the row direction and the column direction are denoted by P.
[0071] Each of FIG. 10B to FIG. 10E is a diagram illustrating an
example of a combination of the multi-band antenna elements 20 to
be operated. In each of the drawings, the multi-band antenna
elements 20 to be operated are hatched. The multi-band antenna
elements 20, which are not hatched, are in the non-operation
state.
[0072] In the example illustrated in FIG. 10B, all of the
multi-band antenna elements 20 are put into the operation state.
The pitch of the multi-band antenna elements 20 in the operation
state in the longitudinal direction and the lateral direction is P,
and the pitch in the 45.degree. oblique direction is equal to
(2.sup.1/2/2)P. Therefore, the maximum value of the pitch becomes
P. In the example illustrated in FIG. 10C, the multi-band antenna
elements 20 in the operation state and the multi-band antenna
elements 20 in the non-operation state are arranged in a checkered
pattern. In this case, the pitch of the multi-band antenna elements
20 in the operation state in the longitudinal direction and the
lateral direction is P and the pitch in the 45.degree. oblique
direction is 2.sup.1/2P. The maximum value of the pitch is given as
2.sup.1/2P which is the pitch of the two multi-band antenna
elements 20 arranged in the oblique direction. In the example
illustrated in FIG. 10D, the multi-band antenna elements 20
included in both of the odd-numbered row and the odd-numbered
column are in the operation state, and the other multi-band antenna
elements 20 are in the non-operation state. In this case, the pitch
of the multi-band antenna elements 20 in the operation state in the
lateral direction and the longitudinal direction is 2P and the
pitch in the 45.degree. oblique direction is 2.sup.1/2P. At this
time, the maximum value of the pitch is given as the pitch 2P in
the longitudinal direction and the lateral direction.
[0073] In the example illustrated in FIG. 10E, rows of the
multi-band antenna elements all of which are set to be in the
non-operation state are added between rows adjacent to each other
in the longitudinal direction of the multi-band antenna elements
forming the checkered pattern. Thus, the plurality of multi-band
antenna elements 20 in the operation state has a relative
positional relationship in which the pitch in the longitudinal
direction is increased while maintaining the pitch in the lateral
direction. In this case, the pitch of the multi-band antenna
elements 20 in the lateral direction is P, and the pitch in the
longitudinal direction is 2P. The pitch in the oblique direction is
(4/5.sup.1/2)P. The maximum value of the pitch is given by 2P that
is the pitch in the longitudinal direction.
[0074] In the examples of FIG. 10D and FIG. 10E, the maximum values
of the pitches are the same, but the values of the pitches in other
various directions are different from each other. Therefore, the
directivity characteristic of the examples above in the operation
state are different from each other. A combination in which a
preferred directivity characteristic is obtained may be employed
depending on the actual use form.
[0075] Next, an excellent effect of the third embodiment will be
described.
[0076] In the third embodiment, it is possible to operate at three
or more different frequencies by changing the maximum value of the
pitch by variously changing the combination of the multi-band
antenna elements 20 in the operation state. As examples illustrated
in FIG. 10D and FIG. 10E, even when the maximum values of the
pitches are the same, it is possible to differentiate the
combination of the multi-band antenna elements 20 in the operation
state. As described above, it is possible to obtain an effect that
the degree of freedom of the combination of the multi-band antenna
elements 20 to be in the operation state increases.
[0077] In the third embodiment, 36 multi-band antenna elements 20
are arranged in six rows and six columns, but the number of
multi-band antenna elements 20 and the arrangement form thereof may
be changed.
Fourth Embodiment
[0078] Next, an antenna module according to a fourth embodiment
will be described with reference to FIG. 11A and FIG. 11B.
Hereinafter, the description of the configuration common to that of
the antenna module according to the first embodiment will be
omitted.
[0079] FIG. 11A is a plan view of the plurality of multi-band
antenna elements 20 of an antenna module according to a fourth
embodiment. In the first embodiment, the plurality of multi-band
antenna elements 20 (FIG. 1A) is arranged in a matrix, that is, in
the grid points of a square grid. In the fourth embodiment, the
plurality of multi-band antenna elements 20 is arranged at the
positions of the grid points of a triangular grid. Focusing on one
multi-band antenna element 20, arranged are six multi-band antenna
elements 20 closest to the multi-band antenna element 20 of
interest, and six closest multi-band antenna elements 20 are
arranged at positions corresponding to vertices of a regular
hexagon. The maximum value of the pitch of the multi-band antenna
elements 20 is given by ((3.sup.1/2)/2)P when the length of one
side of the regular hexagon is denoted as P.
[0080] When all of the multi-band antenna elements 20 are put into
the operation state, the maximum value of the pitch of the
multi-band antenna elements 20 in the operation state becomes equal
to ((3.sup.1/2)/2)P. At this time, it is preferable to operate the
multi-band antenna elements 20 at an operation frequency determined
by a wavelength that is two times the ((3.sup.1/2)/2)P that is the
maximum value of the pitch.
[0081] FIG. 11B is a diagram illustrating an example in which some
of the multi-band antenna elements 20 are operated. In FIG. 11B,
the multi-band antenna elements 20 in the operation state are
hatched. Also, in the fourth embodiment, the multi-band antenna
elements 20 in the operation state may be selected so as to realize
an optimum combination in accordance with the operation
frequency.
[0082] Also, in the fourth embodiment, as with the first
embodiment, it is possible to obtain an excellent effect that one
array antenna is capable of supporting a plurality of frequencies.
Further, when focusing on one multi-band antenna element 20, since
the closest multi-band antenna elements 20 are arranged in six
directions, it is possible to suppress the grating lobes in more
azimuths than the arrangement in the matrix. As the result, it is
possible to obtain an excellent effect that the aperture efficiency
of the array antenna is increased.
Fifth Embodiment
[0083] An antenna module according to a fifth embodiment will be
described with reference to FIG. 12.
[0084] FIG. 12 is a perspective view of a conductor portion and a
diagram illustrating a path of a feed line system of an antenna
module according to a fifth embodiment. The dielectric substrate is
provided with the first ground conductor layer 31, a plurality of
first conductor patterns 201, and a plurality of second conductor
patterns 202. One first conductor pattern 201 and one second
conductor pattern 202 form one multi-band antenna element 20.
[0085] When the thickness direction of the dielectric substrate is
defined as the up-down direction, the first conductor pattern 201
is disposed above the first ground conductor layer 31. The
plurality of first conductor patterns 201 is arranged at equal
intervals in two directions (row direction and column direction)
parallel to the upper surface of the dielectric substrate. The
plurality of second conductor patterns 202 is disposed above the
first conductor patterns 201 corresponding to the plurality of
first conductor patterns 201. The second conductor pattern 202 is
smaller than the first conductor pattern 201, and is disposed so as
to at least partially overlap with the first conductor pattern 201
corresponding thereto in plan view. In FIG. 12, an example is
illustrated in which the second conductor pattern 202 is disposed
inside the first conductor pattern 201. The planer shape of each of
the first conductor pattern 201 and the second conductor pattern
202 is a square shape or a rectangular shape.
[0086] A first feed line network 521 includes a plurality of first
feed lines 511, and a second feed line network 522 includes a
plurality of second feed lines 512. For example, a pad is provided
as corresponding to each of the plurality of first feed lines 511
and the plurality of second feed lines 512, and the plurality of
first feed lines 511 and the plurality of second feed lines 512 are
connected to the radio frequency circuit via the pads. Some of the
plurality of first conductor patterns 201 are coupled to the first
feed lines 511 respectively, and the remaining first conductor
patterns 201 are not coupled to the feed lines. With this
configuration, some of the first conductor patterns 201 are
selectively excited by the first feed line network 521. All of the
second conductor patterns 202 are coupled to the second feed lines
512 respectively, and are excited by the second feed line network
522.
[0087] As an example, 36 first conductor patterns 201 and 36 second
conductor patterns 202 are arranged in a matrix with six rows and
six columns, respectively. The first feed line network 521 excites
the first conductor patterns 201 positioned in the odd-numbered row
and in the odd-numbered column at the same time. That is, the first
conductor patterns 201 are excited every other row in the row
direction and every other column in the column direction. In FIG.
12, the first conductor patterns 201 and the second conductor
patterns 202 to be excited are hatched.
[0088] The plurality of first conductor patterns 201 is connected
to the first ground conductor layer 31 using via conductors 32
provided in the dielectric substrate, respectively.
[0089] The plurality of first conductor patterns 201 excited by the
first feed line network 521 constitutes a first array antenna. The
plurality of second conductor patterns 202 constitutes a second
array antenna. The resonant frequency of each of the second
conductor patterns 202 is higher than the resonant frequency of
each of the first conductor patterns 201. The second array antenna
constituted by the second conductor patterns 202 operates in the
frequency band higher than the frequency band in which the first
array antenna constituted by the first conductor patterns 201
operates.
[0090] Next, an excellent effect obtained by adopting the
configuration of the antenna module according to the fifth
embodiment will be described.
[0091] The first array antenna and the second array antenna that
operate at mutually different frequencies are arranged overlapping
with each other in the thickness direction of the dielectric
substrate, whereby it is possible to reduce the size of the
multi-band antenna module that operates in two frequency bands.
[0092] The first conductor pattern 201 disposed below the second
conductor pattern 202 is connected to the first ground conductor
layer 31 by using the via conductor 32, and the dimension of the
first conductor pattern 201 is deviated from a suitable dimension
in accordance with the resonant frequency of the second conductor
pattern 202. Therefore, when viewed from the first conductor
pattern 201, the ground for antenna constituted by the second
conductor patterns 202 is disposed immediately below the first
conductor pattern 201.
[0093] The size of the first conductor pattern 201 that functions
as the ground for antenna for the second conductor pattern 202 is
determined by the antenna design. The size of the dielectric
substrate depends on various factors that are independent from the
characteristics required for the antenna. Therefore, the size of
the actual ground for antenna may be different from the size of the
ground for antenna at the time of the antenna design in some cases.
When the size of the ground for antenna is different from the size
at the time of design, the designed antenna characteristics may not
be obtained. In this case, it is necessary to redo the antenna
design. In the fifth embodiment, the size of the first conductor
pattern 201, which is the ground for antenna viewed from the second
conductor pattern 202, is determined at the time of design.
Therefore, in the antenna using the second conductor pattern 202 as
a radiating element, it is possible to ensure the designed antenna
characteristics.
[0094] When viewed from the first conductor pattern 201, the first
ground conductor layer 31 functions as the ground for antenna, and
the via conductor 32 functions as a short pin that short-circuits
the first conductor pattern 201 to the first ground conductor layer
31. Thus, the first conductor pattern 201 operates as a planar
inverted-F antenna. With this configuration, when the operation
frequency band is the same, it is possible to make the radiating
element formed of the first conductor pattern 201 smaller than the
radiating element of the patch antenna without the short pins.
[0095] By reducing each of the plurality of first conductor
patterns 201 in size, it is possible to arrange the plurality of
first conductor patterns 201 at narrow intervals. As the result, it
is possible to reduce the interval between the second conductor
patterns 202. By decreasing the arrangement period (pitch) of the
plurality of second conductor patterns 202, it is possible to
suppress the grating lobes. In order to sufficiently suppress the
grating lobes, it is preferable to set the arrangement period of
the second conductor patterns 202 to be equal to or less than the
free space wavelength determined by the operation frequency.
[0096] When the plurality of second conductor patterns 202 is
arranged at the suitable interval in accordance with the operation
frequency of the second array antenna, the interval between the
first conductor patterns 201 becomes narrower than the suitable
interval in accordance with the operation frequency of the first
array antenna. When the interval between the first conductor
patterns 201 becomes narrower than the suitable interval, the
isolation characteristic between the first conductor patterns 201
is deteriorated. In the fifth embodiment, since the plurality of
first conductor patterns 201 is selectively excited every other row
in the row direction and every other column in the column
direction, it is possible to suppress the deterioration in the
isolation characteristic.
[0097] Next, a modification of the fifth embodiment will be
described.
[0098] In the fifth embodiment, the plurality of first conductor
patterns 201 is excited at every other row in the row direction and
every other column in the column direction, but the first conductor
patterns 201 may be excited at every third or higher order row in
the row direction and every third or higher order column in the
column direction. The interval between the first conductor patterns
201 that are targets to be excited may be set to a suitable value
in accordance with the operation frequency of the first array
antenna.
[0099] In the fifth embodiment, the 36 first conductor patterns 201
and the 36 second conductor patterns 202 are arranged in a matrix
with six rows and six columns, but the number of the first
conductor patterns 201 and the second conductor patterns 202 are
not limited to 36. For example, more generally, the conductor
patterns may be arranged in a matrix with n rows and m columns.
Here, n and m are integers equal to or greater than one. Further,
the first conductor pattern 201 and the second conductor pattern
202 are not necessarily arranged in a matrix.
[0100] In the fifth embodiment, each of the multi-band antenna
elements 20 includes two conductor patterns corresponding to two
operation frequencies, that is, the first conductor pattern 201 and
the second conductor pattern 202. By adopting the configuration
that each of the plurality of multi-band antenna elements 20
includes three or more conductor patterns respectively
corresponding to three or more operation frequencies, it is also
possible to realize an antenna module capable of operating at three
or more operation frequencies.
[0101] In the antenna module according to the modification of the
fifth embodiment capable of operating at two or more operation
frequencies, when one operation frequency is selected from the
plurality of operation frequencies, the multi-band antenna elements
20 including the conductor patterns coupled to the feed lines among
the plurality of conductor patterns corresponding to the selected
operation frequency become the power feed targets, and no power is
fed to the remaining multi-band antenna elements 20. In other
words, in the antenna module according to the present modification
of the fifth embodiment, among the conductor patterns corresponding
to the selected operation frequency, the conductor patterns of the
multi-band antenna elements 20 selected as the power feed targets
are coupled to the feed lines, and the conductor patterns of the
remaining multi-band antenna elements 20 are not coupled to the
feed lines. The conductor pattern operates as an antenna by being
coupled to one of the plurality of feed lines. When the selected
operation frequency changes, the combination of the multiple
multi-band antenna elements 20, which include the conductor
patterns coupled to the feed lines among the conductor patterns
corresponding to the selected operation frequency, also
changes.
[0102] In the fifth embodiment, the first feed line 511 is coupled
to only some of the first conductor patterns 201 to be excited
among the plurality of first conductor patterns 201. However, the
first feed lines 511 may be coupled to all of the first conductor
patterns 201, respectively. In this case, the power is fed to the
first conductor patterns 201 via the first feed lines 511 coupled
to the first conductor patterns 201 to be excited, and no power is
fed via other first feed lines 511. The function of feeding power
via some of the first feed lines 511 and not feeding power via
other feed lines may be provided to the radio frequency integrated
circuit element connected to the first feed lines 511.
Sixth Embodiment
[0103] Next, an antenna module according to a sixth embodiment will
be described with reference to FIG. 13A and FIG. 13B. Hereinafter,
the description of the configuration common to the antenna module
according to the fifth embodiment (FIG. 12) will be omitted.
[0104] FIG. 13A is a plan view of an antenna module according to a
sixth embodiment, and schematically illustrates a connection form
of feed lines. In the fifth embodiment, the multi-band antenna
elements 20 constituted of the first conductor pattern 201 and the
second conductor pattern 202 are respectively arranged in a matrix
with six rows and six columns, but in the sixth embodiment, the
multi-band antenna elements 20 are arranged in a matrix with five
rows and five columns.
[0105] In plan view, the second conductor pattern 202 overlaps with
the first conductor pattern 201 disposed at the corresponding
position, and is disposed inside the first conductor pattern 201.
The plurality of first conductor patterns 201 is disposed inside
the outer peripheral line of the first ground conductor layer 31 in
plan view.
[0106] The plurality of first feed lines 511 is coupled to the
first conductor patterns 201 to be excited at first coupling points
212, respectively. As the first conductor patterns 201 to be
excited, the first conductor patterns 201 in the odd-numbered row
and in the odd-numbered column at the same time are selected. The
plurality of second feed lines 512 is coupled to the plurality of
second conductor patterns 202 at second coupling points 213,
respectively. The via conductor 32 that connects the first
conductor pattern 201 and the first ground conductor layer 31 is
disposed between the first coupling point 212 and the second
coupling point 213 in plan view.
[0107] In FIG. 13A, the first feed lines 511 and the second feed
lines 512 are described as not overlapping with each other, but
actually, the first feed lines 511 and the second feed lines 512
may be disposed over a plurality of inner layers in the dielectric
substrate, and may overlap with or intersect with each other in
plan view.
[0108] FIG. 13B is a sectional view taken along the dash-dotted
line 13B-13B in FIG. 13A. The first ground conductor layer 31 is
provided in the inner layer of the dielectric substrate 30. When
the thickness direction of the dielectric substrate 30 is defined
as the up-down direction, the first conductor patterns 201 are
disposed above the first ground conductor layer 31, and the second
conductor patterns 202 are disposed above the first conductor
patterns 201. The via conductor 32 is provided for each of the
first conductor patterns 201, and the via conductor 32 connects the
corresponding first conductor pattern 201 to the first ground
conductor layer 31.
[0109] Another ground conductor layer 35 is provided below the
first ground conductor layer 31. The ground conductor layer 35 is
connected to the first ground conductor layer 31 by a ground via
conductor 36. Wiring lines 511B and 512B are provided between the
first ground conductor layer 31 and the ground conductor layer 35
below the first ground conductor layer 31.
[0110] A via conductor 511A extends upward from the lower side of
the first ground conductor layer 31 passing through an opening
(clearance hole) provided in the first ground conductor layer 31,
and is coupled to the first coupling point 212 of the first
conductor pattern 201. The via conductor 511A and the wiring line
511B constitute the first feed line 511.
[0111] A via conductor 512A extends upward from the lower side of
the first ground conductor layer 31 passing through an opening
(clearance hole) provided in the first ground conductor layer 31.
Further, the via conductor 512A extends upward from the lower side
of the first conductor pattern 201 passing through an opening
(clearance hole) provided in the first conductor pattern 201, and
is coupled to the second coupling point 213 of the second conductor
pattern 202. The via conductor 512A and the wiring line 512B
constitute the second feed line 512. When focusing on the one
multi-band antenna element 20, the via conductor 32 that connects
the first conductor pattern 201 to the first ground conductor layer
31 is disposed between the via conductor 511A that is part of the
first feed line 511 and the via conductor 512A that is part of the
second feed line 512.
[0112] Next, an excellent effect obtained by adopting the
configuration of the antenna module according to the sixth
embodiment will be described.
[0113] Also, in the sixth embodiment, it is possible to obtain the
same effect as that of the fifth embodiment (FIG. 12). Further, in
the sixth embodiment, the via conductor 32 connected to the first
ground conductor layer 31 is disposed between the via conductor
511A that is part of the first feed line 511 and the via conductor
512A that is part of the second feed line 512. Accordingly, it is
possible to ensure the sufficient isolation between the first feed
line 511 and the second feed line 512.
Seventh Embodiment
[0114] Next, an antenna module according to a seventh embodiment
will be described with reference to FIG. 14A and FIG. 14B.
Hereinafter, the description of the configuration common to the
antenna module according to the sixth embodiment (FIG. 13A and FIG.
13B) will be omitted.
[0115] FIG. 14A is a plan view of two multi-band antenna elements
20 of the antenna module according to the seventh embodiment. In
plan view, the second conductor pattern 202 is disposed inside the
first conductor pattern 201. In FIG. 14A, the first conductor
pattern 201 in the left side is the excitation target, and the
first conductor pattern 201 in the right side is not the excitation
target. In the sixth embodiment, one via conductor 32 (FIG. 13A) is
provided for each of the plurality of first conductor patterns 201.
Whereas, in the seventh embodiment, a plurality of, for example,
six via conductors 32 are provided for each of the first conductor
patterns 201. In plan view, the plurality of via conductors 32 is
disposed so as to surround the second coupling point 213. For
example, the plurality of via conductors 32 is arranged with equal
intervals on a circumference centered at the second coupling point
213.
[0116] FIG. 14B is a sectional view taken along the dash-dotted
line 14B-14B in FIG. 14A. In the cross-section illustrated in FIG.
14B, the via conductors 32 are respectively disposed on each side
of the via conductor 512A of the second feed line 512.
[0117] Next, an excellent effect obtained by adopting the
configuration of the antenna module according to the seventh
embodiment will be described. In the sixth embodiment, it is
possible to ensure the isolation between the via conductor 511A and
the via conductor 512A corresponding to each other that are
respectively connected to the first conductor pattern 201 and the
second conductor pattern 202. In the seventh embodiment, it is
possible to shield the via conductor 512A in all azimuths, as well
as to ensure the isolation between the via conductor 511A and the
via conductor 512A corresponding to each other.
Eighth Embodiment
[0118] Next, an antenna module according to an eighth embodiment
will be described with reference to FIG. 15A. Hereinafter, the
description of the configuration common to the antenna module
according to the sixth embodiment (FIG. 13A and FIG. 13B) will be
omitted.
[0119] FIG. 15A is a sectional view of the antenna module according
to the eighth embodiment. In the sixth embodiment, the ground
conductor layer is not provided above the first ground conductor
layer 31 (FIG. 13B). In the eighth embodiment, a second ground
conductor layer 37 is provided in the same layer as the first
conductor pattern 201. A gap is provided between the second ground
conductor layer 37 and the first conductor pattern 201. The second
ground conductor layer 37 is connected to the first ground
conductor layer 31 below the second ground conductor layer 37 using
a ground via conductor 39.
[0120] Next, an excellent effect obtained by adopting the
configuration of the antenna module according to the eighth
embodiment will be described. In the eighth embodiment, the second
ground conductor layer 37 is disposed in the same layer as the
first conductor pattern 201, but both are not connected to each
other in the same layer. Accordingly, as with the fifth embodiment,
the dimension of the first conductor pattern 201, which
substantially functions as the ground for the second conductor
pattern 202, does not depend on the size of the dielectric
substrate 30. Therefore, even when the size of the dielectric
substrate 30 is changed from the precondition of the antenna
design, it is possible to ensure the desired antenna
characteristics.
[0121] Further, it is possible to dispose a strip line between the
first ground conductor layer 31 and the second ground conductor
layer 37.
[0122] FIG. 15B is a sectional view of an antenna module according
to a modification of the eighth embodiment. In the eighth
embodiment, the wiring line 511B that is part of the first feed
line 511 (FIG. 15A) is disposed below the first ground conductor
layer 31. In the modification illustrated in FIG. 15B, the wiring
line 511B is disposed between the first ground conductor layer 31
and the second ground conductor layer 37. In the present
modification, since the wiring line 511B is disposed above the
first ground conductor layer 31, it is possible to obtain an effect
that routing of the wiring line is facilitated compared with a
configuration in which the wiring line is disposed only below the
first ground conductor layer 31.
[0123] As illustrated in FIG. 15C, the wiring line 512B of the
second feed line 512 coupled to the second conductor pattern 202 as
well as the wiring line 511B may be arranged between the first
ground conductor layer 31 and the second ground conductor layer
37.
Ninth Embodiment
[0124] Next, an antenna module according to a ninth embodiment will
be described with reference to FIG. 16A. Hereinafter, the
description of the configuration common to the antenna module
according to the sixth embodiment (FIG. 13A and FIG. 13B) will be
omitted.
[0125] FIG. 16A is a sectional view of the antenna module according
to the ninth embodiment. In the ninth embodiment, a first radio
frequency integrated circuit 41 and a second radio frequency
integrated circuit 42 are mounted on the lower surface of the
dielectric substrate 30. The first radio frequency integrated
circuit 41 is connected to some of the first conductor patterns 201
using the first feed lines 511, and transmits/receives a radio
frequency signal to/from the first conductor patterns 201. The
second radio frequency integrated circuit 42 is connected to the
second conductor patterns 202 using the second feed lines 512, and
transmits/receives a radio frequency signal to/from the second
conductor patterns 202.
[0126] The other ground conductor layer 35 is provided below the
first ground conductor layer 31 and further, another ground
conductor layer 38 is provided below the ground conductor layer 35.
The wiring lines constituting the first feed lines 511 are disposed
between the ground conductor layer 35 and the ground conductor
layer 38, and the wiring lines constituting the second feed lines
512 are disposed between the first ground conductor layer 31 and
the ground conductor layer 35.
[0127] Next, an excellent effect obtained by adopting the
configuration of the antenna module according to the ninth
embodiment will be described. In the ninth embodiment, it is
possible to reduce the size compared with the configuration in
which the antenna module according to the sixth embodiment (FIG.
13A and FIG. 13B) and the radio frequency integrated circuit are
mounted on a mounting substrate such as a motherboard, and the
antenna module and the radio frequency integrated circuit are
connected by a wiring line on the motherboard. Further, by
configuring the first radio frequency integrated circuit 41 and the
second radio frequency integrated circuit 42 by independent
integrated circuit elements, it is possible to easily ensure the
sufficient isolation between frequencies. For example, when the
operation frequency bands of the first conductor pattern 201 and
the second conductor pattern 202 are the 28 GHz band and the 60 GHz
band, respectively, it is possible to prevent the mutual
interference between the radio frequency circuit for the 28 GHz
band and the radio frequency circuit for the 60 GHz band.
[0128] In addition to the first radio frequency integrated circuit
41 and the second radio frequency integrated circuit 42, a
resistance element, an inductor, a capacitor, a baseband integrated
circuit, a DC-DC converter, and the like may be mounted on the
dielectric substrate 30. The first radio frequency integrated
circuit 41, the second radio frequency integrated circuit 42, and
the like may be shielded, as necessary. For example, it is
preferable to cover the first radio frequency integrated circuit
41, the second radio frequency integrated circuit 42, and the like
with a shield can. Alternatively, the first radio frequency
integrated circuit 41, the second radio frequency integrated
circuit 42, and the like may be sealed with sealing resin, and a
shielding conductor film may be formed on the surface of the
sealing resin.
[0129] Next, an antenna module according to a first modification of
the ninth embodiment will be described with reference to FIG.
16B.
[0130] FIG. 16B is a sectional view of the antenna module according
to the first modification of the ninth embodiment. In the ninth
embodiment, the first radio frequency integrated circuit 41 that
excites the first conductor pattern 201 and the second radio
frequency integrated circuit 42 that excites the second conductor
pattern 202 are configured by the independent elements, but in the
present modification, the functions of both of the elements are
realized by one integrated circuit element 43. As illustrated in
FIG. 16B, the integrated circuit element 43 includes both a first
radio frequency circuit that excites the first conductor pattern
201 and a second radio frequency circuit that excites the second
conductor pattern 202. In the first modification of the ninth
embodiment, it is possible to reduce the number of components as
compared with the ninth embodiment.
[0131] In the first modification of the ninth embodiment, the first
feed line 511 and the second feed line 512 are disposed in layers
that are different from each other, but they may be arranged in the
same layer. Further, each of the first feed line 511 and the second
feed line 512 may be disposed across a plurality of layers.
[0132] Next, an antenna module according to a second modification
of the ninth embodiment will be described with reference to FIG.
17.
[0133] FIG. 17 is a sectional view of the antenna module according
to the second modification of the ninth embodiment. An integrated
circuit element 44 is mounted on the lower surface of the
dielectric substrate 30. In the first modification of the ninth
embodiment (FIG. 16B), the first feed line 511 is connected to some
of the first conductor patterns 201, but in the second
modification, the feed lines are not connected to any of the first
conductor patterns 201. That is, each of the multi-band antenna
elements 20 has the same structure as that of the multi-band
antenna element 20 of the antenna module according to the first
embodiment (FIG. 1B). The second conductor patterns 202 of all of
the multi-band antenna elements 20 are connected to the integrated
circuit element 44 by the second feed lines 512. The integrated
circuit element 44 includes the function of the radio frequency
integrated circuit element 52 of the antenna module according to
the first embodiment (FIG. 2).
[0134] The integrated circuit element 44 selects the multi-band
antenna elements 20 to be operated from the plurality of multi-band
antenna elements 20 in accordance with the frequency of the radio
wave transmitted/received, and feeds power to the second conductor
patterns 202 of the selected multi-band antenna elements 20. No
power is fed to the second conductor patterns 202 of the multi-band
antenna elements 20 that are not selected. In the second
modification of the ninth embodiment, the one integrated circuit
element 44 is capable of operating the multi-band antenna element
20 at a plurality of operation frequencies. Therefore, in the
second modification, as in the first modification, it is possible
to reduce the number of components as compared with the ninth
embodiment.
Reference Example
[0135] Next, an antenna module according to a reference example
will be described with reference to FIG. 18. Hereinafter, the
description of the configuration common to the antenna module
according to the eighth embodiment (FIG. 15A) will be omitted.
[0136] FIG. 18 is a sectional view of the antenna module according
to the reference example. In the eighth embodiment (FIG. 15A), the
plurality of first conductor patterns 201 and the plurality of
second conductor patterns 202 are respectively disposed and
constitute the first array antenna and the second array antenna. In
the reference example, one first conductor pattern 201 and one
second conductor pattern 202 are disposed. The plurality of via
conductors 32 that connect the second conductor pattern 202 and the
first ground conductor layer 31 is disposed so as to surround the
via conductor 512A that constitutes part of the second feed line
512 in plan view. The wiring line 511B that constitutes part of the
first feed line 511 is disposed between the first ground conductor
layer 31 and the second ground conductor layer 37.
[0137] Next, an excellent effect obtained by adopting the
configuration of the antenna module according to the reference
example will be described.
[0138] Also, in the reference example, as with the eighth
embodiment, the second ground conductor layer 37 is separated from
the first conductor pattern 201 in the same layer. With this
configuration, the dimension of the first conductor pattern 201
that functions as the ground for antenna of the second conductor
pattern 202 is fixed regardless of the dimension of the dielectric
substrate 30. Therefore, it is possible to suppress the change of
the characteristics of the antenna, in which the second conductor
pattern 202 is the radiating element, from the desired
characteristics at the time of antenna design.
[0139] It is needless to say that the embodiments described above
are illustrative and that partial substitutions or combinations of
the configurations described in different embodiments may be
possible. Similar operational effects according to the similar
configuration in the plurality of embodiments will not be described
one by one for each embodiment. Further, the present disclosure is
not limited to the above-described embodiments. For example, it
will be apparent to those skilled in the art that various
modifications, improvements, combinations, and the like may be
made.
[0140] 20 MULTI-BAND ANTENNA ELEMENT
[0141] 21 ARRAY ANTENNA
[0142] 30 DIELECTRIC SUBSTRATE
[0143] 31 FIRST GROUND CONDUCTOR LAYER
[0144] 32 VIA CONDUCTOR
[0145] 35 GROUND CONDUCTOR LAYER
[0146] 36 GROUND VIA CONDUCTOR
[0147] 37 SECOND GROUND CONDUCTOR LAYER
[0148] 38 GROUND CONDUCTOR LAYER
[0149] 39 GROUND VIA CONDUCTOR
[0150] 41 FIRST RADIO FREQUENCY INTEGRATED CIRCUIT (FIRST RFIC)
[0151] 42 SECOND RADIO FREQUENCY INTEGRATED CIRCUIT (SECOND
RFIC)
[0152] 43, 44 INTEGRATED CIRCUIT ELEMENT
[0153] 50 ANTENNA DRIVE UNIT
[0154] 51 FEED LINE
[0155] 52 RADIO FREQUENCY INTEGRATED CIRCUIT ELEMENT (RFIC)
[0156] 53 BASEBAND INTEGRATED CIRCUIT ELEMENT (BBIC)
[0157] 54 CONTROLLER
[0158] 60 INTERMEDIATE FREQUENCY AMPLIFIER
[0159] 61 UP-DOWN CONVERSION MIXER
[0160] 62 TRANSMISSION/RECEPTION CHANGEOVER SWITCH
[0161] 63 POWER DIVIDER
[0162] 64 PHASE SHIFTER
[0163] 65 ATTENUATOR
[0164] 66 TRANSMISSION/RECEPTION CHANGEOVER SWITCH
[0165] 67 POWER AMPLIFIER
[0166] 68 LOW-NOISE AMPLIFIER
[0167] 69 TRANSMISSION/RECEPTION CHANGEOVER SWITCH
[0168] 201 FIRST CONDUCTOR PATTERN
[0169] 202 SECOND CONDUCTOR PATTERN
[0170] 203, 204, 205, 206, 207, 208 CONDUCTOR PATTERN
[0171] 209 SLOT
[0172] 210 FEED LINE
[0173] 211 SLOT
[0174] 212 FIRST COUPLING POINT
[0175] 213 SECOND COUPLING POINT
[0176] 511 FIRST FEED LINE
[0177] 511A VIA CONDUCTOR
[0178] 511B WIRING LINE
[0179] 512 SECOND FEED LINE
[0180] 512A VIA CONDUCTOR
[0181] 512B WIRING LINE
[0182] 521 FIRST FEED LINE NETWORK
[0183] 522 SECOND FEED LINE NETWORK
* * * * *